/****************************************************************************
 *
 * Copyright 2019 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/****************************************************************************
 * os/binfmt/binfmt_loadmodule.c
 *
 *   Copyright (C) 2009, 2014, 2017-2018 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <tinyara/config.h>

#include <sched.h>
#include <debug.h>
#include <errno.h>

#include <tinyara/envpath.h>
#include <tinyara/sched.h>
#include <tinyara/kmalloc.h>
#include <tinyara/binfmt/binfmt.h>

#include "binfmt.h"

#ifdef CONFIG_BINFMT_ENABLE

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: load_default_priority
 *
 * Description:
 *   Set the default priority of the module to be loaded.  This may be
 *   changed (1) by the actions of the binary format's load() method if
 *   the binary format contains priority information, or (2) by the user
 *   between calls to load_module() and exec_module().
 *
 * Returned Value:
 *   Zero (OK) is returned on success; Otherwise a negated errno value is
 *   returned.
 *
 ****************************************************************************/

static int load_default_priority(FAR struct binary_s *bin)
{
	struct sched_param param;
	int ret;

	/* Get the priority of this thread */

	ret = sched_getparam(0, &param);
	if (ret < 0) {
		berr("ERROR: sched_getparam failed: %d\n", ret);
		return ret;
	}

	/* Save that as the priority of child thread */

	bin->priority = param.sched_priority;
	if (bin->priority <= 0) {
		bin->priority = SCHED_PRIORITY_DEFAULT;
	}

	return ret;
}

/****************************************************************************
 * Name: load_absmodule
 *
 * Description:
 *   Load a module into memory, bind it to an exported symbol take, and
 *   prep the module for execution.  bin->filename is known to be an absolute
 *   path to the file to be loaded.
 *
 * Returned Value:
 *   Zero (OK) is returned on success; a negated errno value is returned on
 *   failure.
 *
 ****************************************************************************/

static int load_absmodule(FAR struct binary_s *bin)
{
	FAR struct binfmt_s *binfmt;
	int ret = -ENOENT;

	binfo("Loading %s\n", bin->filename);

	/* Disabling pre-emption should be sufficient protection while accessing
	 * the list of registered binary format handlers.
	 */

	/* Traverse the list of registered binary format handlers.  Stop
	 * when either (1) a handler recognized and loads the format, or
	 * (2) no handler recognizes the format.
	 */

	for (binfmt = g_binfmts; binfmt; binfmt = binfmt->next) {
		/* Use this handler to try to load the format */

		ret = binfmt->load(bin);
		if (ret == OK) {
			/* Successfully loaded -- break out with ret == 0 */

			binfo("Successfully loaded module %s\n", bin->filename);

			/* Save the unload method for use by unload_module */

			bin->unload = binfmt->unload;
			dump_module(bin);
			break;
		}
	}

	return ret;
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: load_module
 *
 * Description:
 *   Load a module into memory, bind it to an exported symbol take, and
 *   prep the module for execution.
 *
 * Returned Value:
 *   This is a internal function so it follows the convention that
 *   0 (OK) is returned on success and a negated errno is returned on
 *   failure.
 *
 ****************************************************************************/

int load_module(FAR struct binary_s *bin)
{
	int ret = -EINVAL;

	/* Verify that we were provided something to work with */

#ifdef CONFIG_DEBUG
	if (bin && bin->filename)
#endif
	{
		if (bin->priority == 0) {
			/* Set the default priority of the new program. */
			ret = load_default_priority(bin);
			if (ret < 0) {
				return ret;
			}
		}

		/* Were we given a relative path?  Or an absolute path to the file to
		 * be loaded?  Absolute paths start with '/'.
		 */

#ifdef CONFIG_LIB_ENVPATH
		if (bin->filename[0] != '/') {
			FAR const char *relpath;
			FAR char *fullpath;
			ENVPATH_HANDLE handle;

			/* Set aside the relative path */

			relpath = bin->filename;
			ret = -ENOENT;

			/* Initialize to traverse the PATH variable */

			handle = envpath_init("PATH");
			if (handle) {
				/* Get the next absolute file path */

				while ((fullpath = envpath_next(handle, relpath)) != NULL) {
					/* Try to load the file at this path */

					bin->filename = fullpath;
					ret = load_absmodule(bin);

					/* Free the allocated fullpath */

					kmm_free(fullpath);

					/* Break out of the loop with ret == OK on success */

					if (ret == OK) {
						break;
					}
				}

				/* Release the traversal handle */

				envpath_release(handle);
			}

			/* Restore the relative path.  This is not needed for anything
			 * but debug output after the file has been loaded.
			 */

			bin->filename = relpath;
		} else
#endif
		{
			/* We already have the one and only absolute path to the file to
			 * be loaded.
			 */

			ret = load_absmodule(bin);
		}
	}

	return ret;
}

#endif							/* CONFIG_BINFMT_ENABLE */
